1. Field of the Invention
The present invention relates to a floating head slider, and more specifically to a floating he ad slider which is used in a magnetic disk apparatus.
2. Description of Related Art
In the past, a floating head slider such as shown in FIGS. 8(A) and 8(B) has been used in a magnetic disk apparatus. The floating head slider 1g in generally used is formed by a rectangularly shaped slider element 71 and slider rails 60 which protrude from the surface of the slider element 71. The slider rails 60 extend along a flow of air, these slider rails 60 making physical contact with a magnetic disk.
In recent years, because of the appearance of high-density magnetic disks, there has been a trend towards the narrowing of the spacing between the floating head slider and the magnetic disk. In particular with regard to what is known as the contact start/stop (hereinafter referred to as CSS) system, the slider can wear down the roughness or protrusions in the surface of the disk, this being the case of the generation of dust.
As the spacing between the floating head slider and the magnetic disk during writing and reading of information becomes narrow, this occurs even when the floating head slider is in the floating condition.
Accompanying this phenomenon, floating dust intrudes in between the floating pressure generating surface of the slider rails and the magnetic disk provided in a disk driving device, this causing a temporary condition in which it is not possible to read and write information.
Additionally, dust becoming attached to the surface of the slider rails causes instability in the floating of the head slider, this resulting in a risk of damage being done to the magnetic disk and floating head slider, caused by the high-speed sliding between it and the magnetic disk.
The dust is generally generated from a surface of the slider or magnetic disk and sometimes generated from a surface of a protection layer of the slider or lubricating layer formed on a surface of the magnetic disk.
To solve the above-described problem, the Japanese Unexamined Patent Publication (KOKAI) No. 61-170922 discloses the provision of a prescribed step level change at the flow edge of air at the slider rail, this step level change causing a complex flow of air, thereby reducing amount of dust that accumulates at the outflow edge of the slider rail.
In the Japanese Unexamined Patent Publication (KOKAI) No. 5-81810, there is disclosed the formation of a V-shaped groove upstream from the air outflow edge on the floating pressure generation surface of the slider rail, this groove capturing the dust in the air flow and preventing it from coming into contact with the surface of the magnetic disk.
In the Japanese Unexamined Patent Publication (KOKAI) No. 4-137286, there is proposed the formation of an acute angle at a taper part of the end of a floating head slider, and the forming of a tapered surface with an acute angle between the outside surface of in the longitudinal direction of the slider rail and the floating pressure generation surface.
In the Japanese Unexamined Patent Publication (KOKAI) No. 6-44719, to provide a floating head slider that solves the problem of accumulated dust in a negative pressure slider, there is a disclosure of the separation of a cross rail formed at the air inflow edge by an open groove, this forming an escape path for the air flow, thereby suppressing the accumulation of dust.
In the Japanese Unexamined Patent Publication (KOKAI) No. 6-333354, there is the disclosure of the use of a cross rail that reaches the air inflow edge, and the elimination of the tapered part. This is a method of eliminating the dust that accumulates in the space between the taper part and the magnetic disk which is not easy to remove even by utilizing the contact stop and start method.
However, the following problems existed with the prior art cited above. Specifically, in the floating head slider of Japanese Unexamined Patent Publication (KOKAI) Nos. 61-170922 and 5-81810, it is possible to reduce the amount of dust that accumulates at the slider rail surface, and particularly at the slider rail outflow edge.
However, because the main accessing system used is a rotary system in which there is undulation about a prescribed rotational axis so as to achieve positioning at a prescribed radiation position, there is a finite angle (known as the yaw angle) that is formed between the longitudinal direction of the floating head slider and the tangential direction of the magnetic disk, the dust that is contained in the air which is taken in becoming affixed to and accumulating on side of the slider rail as well.
If this dust reaches the floating pressure generation surface of the slider rail, it causes an apparent increase in the surface area of the slider rail , so that the floating condition of the slider becomes unstable.
In the floating head slider of the Japanese Unexamined Patent Publication (KOKAI) No. 4-137286, consideration is given to dust being attached to the side of the slider.
However, with the exception of seek access, this configuration dictates that the air flow is divided into two or three parts within the slider rails, and in the case of a head slider that uses negative pressure, which will be described below, because dust becomes selectively attached to the negative pressure generation part even inside the slider, the suppression of dust by this method has no affect on the attachment of dust to the inside of the slider.
While a floating head slider known as a TPC (transverse pressure contour) slider has a level change portion, i.e., a step-like portion, with a depth of , for example, 0.5 to 1.5 .mu.m from the floating pressure generation surface at both sides of the slider rail, with the floating head slider which is disclosed in the Japanese Unexamined Patent Publication (KOKAI) No. H4-137286, even on the outside surface of the slider, it is not possible to completely suppress attachment of dust to the above-described level change part.
In addition, in the case of a floating head slider which uses negative pressure, dust is pulled into a part at which the pressure at the slider rail side of the air outflow side is lower than the ambient air pressure, and in the case of the floating head slider that is disclosed in the Japanese Unexamined Patent Publication (KOKAI) No. 6-333354, the only effect achieved is a suppression of the attachment of dust at the air inflow side of the cross rail, this floating head slider not being capable of preventing instability of the floating condition caused by selective attachment of dust to the negative pressure generation part.
In view of the above-described drawbacks in the prior art, an object of the present invention is to provide a floating head slider in which stable floating and reading and writing of information is possible even if dust becomes attached to the slider rail side walls.